My new GM Performance block showed up this week and I noticed that in the front of the engine at the oil drain back holes that they are not level so oil can flow out and back into the crankcase. Is this normal I didn't even check my old block before asking there is a lot of stuff on it? I know in the rear I should grind them open a little more.

Should I leave it as it is or get out my die grinder and open up the flow

I just checked a block I had in my garage and the holes on it are much bigger and level with each other. Whether it matters or not I dont know There are lots of other places in the lifter valley for oil to drain back to the pan. I wonder if those holes in the front arent a for ventilation between the crankcase and the lifter valley or something? You know, so the oil will drain smoothly without bubbling back up. (you know, like leaving the vent closed on a gas can or on some oil drain pans)

I wouldnt think you should have to worry about them.

Bad Rat 414

09-10-2005 01:48 PM

Those holes behind the timing cover should not affect drain back to the oil pan. I'd hate to think you had that much oil in the top side of your engine. The oil would have to be over 1 " deep. You also have holes over the top of the cam for drainage.

BigDawgsEatFirst

09-10-2005 02:20 PM

Are u teasing us with these new parts.....LOL
Ha,Ha, :thumbup:
Pistons and block look good :D

hause

09-10-2005 02:23 PM

lifter valley

Could It Be Because It Is A Dry Sump Block.

Bumpstick

09-10-2005 02:58 PM

Those holes are not for oil drain back... They are for ventilation more than anything... The timing chain or gearset is lubed mainly via the sump... Some oil may even sling off the chain and into the lifter area but it all drains back via the holes in the lifter area or the back of the block area... Just remember the engine should have a 2-3 degree slant to the rear... ;) (gravity does the rest)